Temperature & Pressure Relief Pipes

[Rory D Marshall]

On an Un-vented hot water cylinder or system boiler, can the pressure relief pipe exit into a clay soil stack?

The pipe isn't able to exit outside, as the exterior face of the builiding is not allowed to be damaged. The clay SV Pipes run inside the building so are you able to run the relief pipe directly into this?

I have spoken to a couple of manufacturer's regarding this and they say it's dependant on the building regs. But I can't seem to find where to view the Building Regulation G3..

Any help appreciated

Thanks

 

[kirkgas]

what do the MI for the unvented cylinder say? the unvented training notes changed late last year to include connection to an internal soil stack using a suitable connection, so i would have thougth they would all be the same now, there is a requirement for the right material to be used and it needs to be fitted in a certain way but an approved installer should know the updated regs (although that isn't 100% correct based on discussions with qualified people lately) ifyou have decided what model to get check online for the MI and all will be clear

 

[Rory D Marshall]

The cylinder being used is a Potterton Gold. But when I spoke to Potterton Technical advice they said they couldn't advise on that particular subject and that i'd have to consult the building regs.

Do you know what the connector type is that you need to connect into a clay sv pipe?

 

[kirkgas]

this is a cut and paste from the potterton gold MI, what you need to comply with the dry trap is a HEPvO
the actual fitting required to connect into the stack will depend on the type/size of pipe fitted, best to let your plumber sort that for himself (if it isnt you who is fitting) as a problem with the stack connection will cause major problems with leaks

3.60 The discharge pipe should not be connected to a soil discharge stack unless it can be demonstrated that that the soil discharge stack is capable of safely withstanding temperatures of the water discharged, in which case, it should:
(a) contain a mechanical seal, not incorporating a water trap, which allows water into the branch pipe without allowing foul air from the drain to be ventilated through the tundish;

(b) be a separate branch pipe with no sanitary appliances connected to it;
(c) if plastic pipes are used as branch pipes carrying discharge from a safety device they should be either polybutalene (PB) to Class S of BS 7291-2:2006 or cross linked polyethylene (

 

[Rory D Marshall]

Thanks for that. I've just purchased a HepVO waste valve so that should be sorted.